All-Electric Kitchen Extension and Sub-Main Distribution – Buckhurst Hill (IG9)

The project brief and core requirements

The client chose an entirely gas-free, all-electric kitchen configuration, requiring the electrical load and circuit layout to be planned around the new appliances and services. The installation scope included:

• Dedicated heavy-duty circuits for cooking appliances.
• An independent ring final circuit designated for multi-zone air-conditioning units.
• General power, secondary distribution and bespoke kitchen lighting grids.

Engineering challenges and spatial assessments

1. Cellar suitability and ingress protection

The kitchen extension was more than 20 metres from the property's incoming electrical service cupboard. To avoid excessive voltage drop and unnecessary structural chasing, a sub-distribution arrangement was selected, with the new consumer unit located in the basement cellar.

Before confirming the position, we assessed the cellar for ambient dampness and potential water ingress to check that the location was suitable for the electrical enclosure and distribution equipment.

2. Sub-main cable routing through a restricted sub-floor

The sub-main was installed using 16mm² three-core Steel Wire Armoured (SWA) cable, protected upstream by a 50A MCB at the main board. The approximately 20-metre route required access through a restricted sub-floor space around two feet high. We routed and secured the cable to keep it clear of potential friction and damage points.

3. Additional surge protection at the cellar board

Although the main consumer unit already had surge protection, the long distance between the origin and the new distribution board can affect the protection level achieved at connected equipment. Following discussion with the building team, we installed a dedicated Type 2 Surge Protection Device (SPD) in the cellar consumer unit to provide additional protection for the kitchen's electronic equipment against transient overvoltages.

Remediating a hidden main earthing and bonding defect

During the under-floor inspection, we found that the main earthing clamp was concealed beneath the sub-floor and inaccessible for inspection and testing. Rather than introduce an inaccessible joint, we installed a new, uninterrupted 10mm² main protective bonding conductor.

The conductor was routed across the joists and out through the property's side alleyway to an accessible external gas meter box. It was terminated using a 6mm lug and a BS 951 bonding clamp.

Commissioning, testing and handover

Following completion of the second-fix work, we carried out dead and live testing using calibrated test equipment. The inspection and test sequence included checks of continuity, insulation resistance, polarity and earth fault loop impedance, as applicable to the installation.

After successful testing, we handed over a NICEIC Electrical Installation Certificate (EIC) and the Building Control Part P compliance notification for the completed work.